Famous Scientists and Their Laws and Discoveries
Exam notes pairing scientists with the laws and discoveries named after them: Newton, Archimedes, Ohm, Mendel, Einstein and the Indian scientists.
By GK24 Editorial Team· Published · 5 min read
Every general science paper carries one or two questions that give a law and ask for the scientist, or give a scientist and ask for the discovery. The facts never change, which makes this the cheapest marks in the subject, but the names are many and the distractors are close, so the only way to be safe is to revise them as pairs and in groups. This note groups the laws by branch, physics first, then chemistry and biology, and ends with the Indian scientists and the prizes attached to them.
Physics: motion, fluids and heat
Isaac Newton stated the three laws of motion and the law of universal gravitation in his Principia of 1687; the first law defines inertia, the second gives force as the rate of change of momentum, and the third pairs every action with an equal and opposite reaction. Newton also gave the law of cooling. Johannes Kepler had earlier given the three laws of planetary motion: planets move in ellipses with the sun at a focus, the line joining a planet to the sun sweeps equal areas in equal times, and the square of the period is proportional to the cube of the mean distance. Archimedes gave the principle of buoyancy, that a body in a fluid is pushed up by a force equal to the weight of the fluid it displaces, and also the law of the lever. Blaise Pascal showed that pressure applied to an enclosed fluid is transmitted undiminished in all directions, the law behind the hydraulic press and hydraulic brakes. Daniel Bernoulli related the pressure, speed and height of a flowing fluid. Robert Hooke stated that stress is proportional to strain within the elastic limit.
Physics: electricity, light and the modern era
Georg Ohm found that current through a conductor is proportional to the potential difference across it at constant temperature, written as V equals I into R. Michael Faraday gave the laws of electromagnetic induction and of electrolysis, Lenz gave the direction of the induced current, Coulomb the inverse square law of force between charges, Joule the heating effect of current, and Kirchhoff the two circuit rules. Willebrord Snell gave the law of refraction of light. In the modern era Max Planck proposed the quantum of energy in 1900, Albert Einstein published the special theory of relativity in 1905 with the relation between mass and energy, explained the photoelectric effect, for which he received the Nobel Prize in Physics, and gave the general theory of relativity in 1915. Relativity is the reason no object with mass can be accelerated to the speed of light in vacuum. Werner Heisenberg gave the uncertainty principle and Niels Bohr the model of the atom with quantised orbits.
Chemistry and the structure of the atom
Antoine Lavoisier, called the father of modern chemistry, gave the law of conservation of mass. Boyle showed that the volume of a gas varies inversely with pressure at constant temperature, Charles that volume varies directly with absolute temperature at constant pressure, Gay-Lussac the same relation for pressure, Dalton the law of partial pressures along with his atomic theory, Avogadro that equal volumes of gases at the same temperature and pressure hold equal numbers of molecules, and Graham that the rate of diffusion of a gas is inversely proportional to the square root of its density. Dmitri Mendeleev arranged the elements by increasing atomic mass in his periodic law, and Henry Moseley corrected the basis to atomic number. The particles of the atom belong to three names: J.J. Thomson discovered the electron in 1897, Ernest Rutherford found the nucleus and named the proton, and James Chadwick discovered the neutron in 1932.
Biology and medicine
Gregor Mendel, working on garden pea, gave the laws of inheritance, namely dominance, segregation and independent assortment, and is called the father of genetics. Charles Darwin explained evolution by natural selection in the Origin of Species of 1859, while Lamarck had argued for the inheritance of acquired characters. Robert Hooke first saw and named the cell in 1665, Anton van Leeuwenhoek saw living cells, and Schleiden and Schwann framed the cell theory, to which Virchow added that a cell comes only from a pre-existing cell. Louis Pasteur gave the germ theory of disease and pasteurisation, Edward Jenner the smallpox vaccine, Alexander Fleming penicillin, and Watson and Crick the double helix of the genetic material.
Indian scientists to remember
| Scientist | Work or law | Note |
|---|---|---|
| C.V. Raman | Raman effect, the scattering of light | Nobel Prize in Physics, 1930 |
| Meghnad Saha | Saha ionisation equation | Thermal ionisation in stars |
| Satyendra Nath Bose | Bose statistics, with Einstein | The boson is named after him |
| Homi Jehangir Bhabha | Cascade theory of electron showers | Architect of India's atomic energy programme |
| Vikram Sarabhai | Cosmic ray research | Father of the Indian space programme |
| Jagadish Chandra Bose | Response of plants; the crescograph | Also early work on radio waves |
| Subrahmanyan Chandrasekhar | Chandrasekhar limit for white dwarfs | Nobel Prize in Physics, 1983 |
| Har Gobind Khorana | Synthesis of nucleotides and the genetic code | Nobel Prize, 1968 |
| Srinivasa Ramanujan | Number theory, infinite series | National Mathematics Day on his birthday |
| Prafulla Chandra Ray | Mercurous nitrite; history of Hindu chemistry | Father of Indian chemistry |
Quick pairs that decide the mark
- Inertia with Newton's first law; buoyancy with Archimedes; hydraulic brakes with Pascal; floating of aeroplanes and the spin of a ball with Bernoulli.
- Electron with Thomson, nucleus and proton with Rutherford, neutron with Chadwick, quantised orbits with Bohr.
- Periodic table by atomic mass with Mendeleev, by atomic number with Moseley.
- Genetics with Mendel, natural selection with Darwin, germ theory with Pasteur, penicillin with Fleming.
Exam Point of View
The question is nearly always a one to one match, so prepare the pairs rather than the theory. Papers favour Newton, Archimedes, Pascal, Ohm, Faraday, Boyle, Charles, Mendel and Darwin, and among Indians C.V. Raman, Homi Bhabha, Vikram Sarabhai, Jagadish Chandra Bose and S. Chandrasekhar. The traps are the near neighbours: Thomson, Rutherford and Chadwick for the three particles; Mendeleev and Moseley for the periodic law; Lamarck and Darwin for evolution; Jenner and Pasteur for vaccines; Boyle and Charles for the gas laws. A second pattern asks for the application: hydraulic brakes for Pascal, the lift of an aeroplane wing for Bernoulli, the floating of a ship for Archimedes. Nobel years for Indian scientists, 1930 for Raman and 1983 for Chandrasekhar, are asked as plain recall.
Important Facts
| Laws of motion and gravitation | Isaac Newton, Principia, 1687 |
|---|---|
| Laws of planetary motion | Johannes Kepler: orbits, areas and periods |
| Principle of buoyancy | Archimedes: upthrust equals weight of fluid displaced |
| Pressure in an enclosed fluid | Pascal law; used in the hydraulic press and brakes |
| Current and potential difference | Ohm law: V equals I into R at constant temperature |
| Electromagnetic induction | Michael Faraday; direction given by Lenz law |
| Relativity | Albert Einstein: special theory 1905, general theory 1915 |
| Discovery of particles | Electron by J.J. Thomson, 1897; neutron by Chadwick, 1932 |
| Periodic law | Mendeleev by atomic mass; Moseley by atomic number |
| Laws of inheritance | Gregor Mendel: dominance, segregation, independent assortment |
| Raman effect | C.V. Raman; Nobel Prize in Physics, 1930 |
| Chandrasekhar limit | S. Chandrasekhar; Nobel Prize in Physics, 1983 |
Practice MCQs on this topic
According to which theory or law can any object with mass not travel as fast as the speed of light in empty space, that is in vacuum?
- A.Dalton law
- B.Corpuscular theory of light
- C.Theory of relativity
- D.Henry law
Show answer
In Einstein's special theory of 1905 the energy required to accelerate a body with mass rises without limit as its speed approaches that of light, so such a body can come close to but never reach the speed of light in vacuum, which is the same for every observer.
Read the full explanation →Who discovered the electron?
- A.Ernest Rutherford
- B.J.J. Thomson
- C.James Chadwick
- D.Niels Bohr
Show answer
Thomson. Working with cathode rays in a discharge tube in 1897, he showed that the rays were a stream of negatively charged particles far lighter than any atom, and he measured their charge to mass ratio, which established the electron as the first known subatomic particle.
Read the full explanation →The neutron was discovered in 1932 by which scientist?
- A.James Chadwick
- B.Eugen Goldstein
- C.Max Planck
- D.Werner Heisenberg
Show answer
By bombarding beryllium with alpha particles he obtained a penetrating radiation that could not be bent by electric or magnetic fields, and he showed it to consist of neutral particles of about the mass of a proton, for which he received the Nobel Prize in Physics.
Read the full explanation →The three laws of planetary motion were given by whom?
- A.Nicolaus Copernicus
- B.Galileo Galilei
- C.Johannes Kepler
- D.Isaac Newton
Show answer
Working on the observations of Tycho Brahe he found that a planet moves in an ellipse with the sun at one focus, that the line from the sun to the planet sweeps equal areas in equal times, and that the square of the orbital period is proportional to the cube…
Read the full explanation →Hydraulic brakes in a motor car work on which principle?
- A.Archimedes principle
- B.Pascal law
- C.Bernoulli principle
- D.Hooke law
Show answer
Pressure applied to an enclosed liquid is transmitted equally and undiminished in every direction, so a small force on the narrow master cylinder of a brake creates a much larger force on the wide piston at each wheel, which is also how a hydraulic press and a hydraulic lift work.
Read the full explanation →Who is known as the father of genetics for the laws of inheritance?
- A.Charles Darwin
- B.Gregor Mendel
- C.Jean Baptiste Lamarck
- D.Hugo de Vries
Show answer
His experiments on garden pea, in which he followed single characters such as seed shape and flower colour through generations, gave the laws of dominance, segregation and independent assortment, and showed that inheritance works through discrete factors rather than a blending of parental traits.
Read the full explanation →Ohm law states that, at constant temperature, the current through a conductor is
- A.inversely proportional to the potential difference across it
- B.directly proportional to the potential difference across it
- C.independent of the potential difference across it
- D.proportional to the square of the potential difference across it
Show answer
Ohm found that for a metallic conductor at a steady temperature the ratio of potential difference to current is a constant, the resistance, which is written as V equals I into R, so doubling the voltage doubles the current.
Read the full explanation →The periodic law based on increasing atomic number, rather than atomic mass, is credited to whom?
- A.Dmitri Mendeleev
- B.Henry Moseley
- C.John Newlands
- D.Johann Dobereiner
Show answer
His study of the characteristic X-rays of the elements showed that the nuclear charge, the atomic number, is the quantity that rises regularly from element to element, and the modern periodic law therefore states that properties are a periodic function of atomic number.
Read the full explanation →C.V. Raman was awarded the Nobel Prize in Physics in which year?
- A.1928
- B.1930
- C.1954
- D.1983
Show answer
Raman announced in 1928 that light scattered by a transparent medium contains components of changed wavelength, a shift that reveals the energy levels of the scattering molecules, and the Nobel Prize in Physics followed in 1930, making him the first Asian to receive a Nobel in a science.
Read the full explanation →Who among the following is called the father of the Indian space programme?
- A.Homi Jehangir Bhabha
- B.Vikram Sarabhai
- C.Satish Dhawan
- D.Meghnad Saha
Show answer
A cosmic ray physicist who founded the Physical Research Laboratory at Ahmedabad, he persuaded the government that a poor country needed space technology for communication, weather and education, set up the rocket launching station at Thumba and built the organisation that became the Indian Space Research Organisation.
Read the full explanation →Frequently Asked Questions
Which theory says that no object with mass can reach the speed of light?
The special theory of relativity, published by Albert Einstein in 1905. As the speed of a massive body rises, the energy needed to accelerate it further grows without limit, so the speed of light in vacuum is a limit that such a body can approach but never reach.
Who discovered the electron, the proton and the neutron?
J.J. Thomson discovered the electron in 1897 through his work on cathode rays, Ernest Rutherford established the nucleus and gave the proton its name, and James Chadwick discovered the neutron in 1932. Papers ask these three names as a set.
What does Pascal law explain in everyday machines?
That pressure applied at one point of an enclosed liquid reaches every other point undiminished. This is why a small force on the narrow piston of a hydraulic press or a brake cylinder produces a large force on the wide piston, and it is the standard application asked in exams.
Why is Mendel called the father of genetics?
Because his breeding experiments on garden pea, published in the eighteen sixties, established that characters are carried by discrete factors and gave the laws of dominance, segregation and independent assortment, which later work recognised as the behaviour of genes.
For what work did C.V. Raman receive the Nobel Prize?
For the Raman effect, the discovery that light scattered by a transparent substance changes in wavelength, which revealed the energy levels of molecules. The work was announced in 1928 and the Nobel Prize in Physics followed in 1930.
Sources
- Science (Class IX and Class X), chapters on motion, force, gravitation, electricity and heredity — NCERT
- Physics Part I and Part II (Class XI), chapters on laws of motion, gravitation and thermodynamics — NCERT
- Chemistry Part I (Class XI), chapters on the structure of the atom and classification of elements — NCERT
